Car Repair Help by Professional Mechanics
Repair Topics /
Engine Sensors-1
/ Engine Sensors-2
MORE: Engine sensor questions
Question: 1999 Dodge Dakota mileage: 90,000. You have touched on
the subject, but I wonder if you might help me. I have low rpm spark plug knock
in my 99 Dakota 4x4. The dealer says I need higher-octane fuel. In your
FAQ archive, I noticed that you told another Dakota owner to check the EGR valve.
Is 96 octane high enough, or do I need an additive (102 boost, etc)? This
pinging is making me crazy. Thanks!
Answer: The EGR valve can cause the pinging but also check the knock sensor.
If the knock sensor is functioning properly, it detects the pinging and retards
the timing. Scan your PCM for trouble codes.
Question: 2002 Chevrolet Monte Carlo mileage: 85,000. Can you please
tell me where the Mass Air Flow sensor is for this car we are having trouble finding
it and replacing it? We have been told that it is under the fender,
NOT THERE. Thank-you
Answer: The Mass Air Flow sensor is located inline with the air
intake system.
Question: 1999 Pontiac Grand Am mileage: 92,000. The crank sensor
is bad and needs to be replaced. I purchased a new crank sensor and a Haynes
book for the car. The Haynes book says that the crank sensor is 0.05 inches
from the crankshaft reluctor ring and it protrudes through the engine block; however,
I can not locate the sensor anywhere. The coil packs (the car has a distributorless
system) are in the back of the engine and I could not get a good look there, but
I have searched everywhere else and have been unsuccessful. Please tell
me where I can find the crank sensor and if there are any useful tips to be employed
when replacing the sensor. Thanks
Answer: The crank angle sensor is located near the coil packs in the side
of the block.
Question: 1998 Pontiac Firebird mileage: 117,000. I've recently
( within the last 25,000 miles) noticed a tendency for the vehicle to stall and
hesitate when it's at operating temperature. I also notice the tach jumping between
500 - 1000 rpm when in drive. The car has a 4 speed automatic and it has been
tuned up about 30,000 miles ago. The coolant sensor has been replaced, but
I'm thinking the TPS sensor needs replacing. During regular driving, she's
ok; it's just at stoplights that the stalling and surging occurs. Am I on
the right track with the TPS sensor?
Answer: Scan the PCM for trouble code, then try replacing the mass air
flow sensor to recheck.
Question: 1999 Mazda B2600 mileage: 93,000. My problem started about 2
months ago and I have not been able to resolve it. The problem is that occasionally
the engine decides to oscillate Rpms when placed in gear (it is a manual transmission),
and on some occasions it takes numerous start attempts to get the engine to run
on its own and I have to let it warm up for 15 minutes before being able to drive
it. Once running it will vary in power when downshifting, while coming to
a stop it will suddenly lurch forward. This problem is not a constant thing
it just comes and goes. There is no common time of occurrence, such as only
when the engine is cold or only hot etc. I have had a mechanic put the engine
on an analyzer and it did not reveal any problems. I replaced the plugs, wires,
fuel filter, catalytic converter, and have added slick 50-fuel treatment along with
running only 93-octane gas, none of this has solved the problem. I am stumped
please help with some advice. Thanks, Ron
Answer: From what you have described, we believe that your problem is
a weak oxygen sensor.
Question: 1993 Buick Skylark 6 cylinder mileage: 130,000. What is
an MAF Sensor. The MAF sensor went bad on my car recently and it cost me $423.00.
What is it and how much do the part alone cost?
Answer: MAF stands for mass airflow sensor and it measures
the quantity of air entering the engine. You can call the Buick parts department
and find out the current cost of the part.
Question: 1994 Chrysler lhs 3.5 V6 mileage: 45,989. When I come
to a stop the tachometer reads about 800 rpm, within 5 seconds I can watch the tachometer
drop about 150-200 rpm's. I have replaced the map sensor. Where else
should I look? By the way, the computer doesn't show any codes.
Answer: Try replacing the oxygen sensor, as it appears it
may be deteriorating.
Question: 1984 Nissan 300 ZX 3 litre V6 mileage: 112,000 km.
My car is a 1984 Nissan 300 ZX with a three speed automatic with an electronic overdrive
for fourth gear. When I switch the overdrive on, it stays in third gear even
when the car is warmed up. The switch and overdrive solenoid are working but
I have been to several auto electricians and they cannot seem to find the fault.
Could you please give me a few suggestions on how to fix my problem?
Thank you.
Answer: The overdrive circuit is controlled by the engine temperature
sensor to prevent it from going into overdrive when the engine is cold. If
the sensor is faulty, it will not allow your transmission to shift into overdrive.
Also, check the thermostat, if it is stuck open, it will not allow the engine to
come up to normal temperature and the transmission will not shift into overdrive.
Question: 2001 Dodge Intrepid mileage: 86,000. I have reason to
believe that I need to replace my Crank Sensor. How do I locate this under
the hood?
Answer: The crank sensor is located on the passenger side of the
engine towards the bottom.
Question: 2003 Dodge Neon, miles: 45,000 My "check engine" light
has been on for the past week. I took it to the dealer and they told me it was because
of my "upstream oxygen sensor". What and where is it, and is it something
I can change myself? Is this the same thing as the "oxygen sensor" in my exhaust
manifold?
Answer: Yes, it is in the exhaust manifold. It is easy
to change when the engine is cold.
Question: 1998 Volkswagen Passat mileage: 50,000. Where is the knock
sensor, and how do I replace it.
Answer: Your engine has two knock sensors, they are located
on the front of the engine about center. Replace them by unplugging the wire
connector and removing mounting bolt.
MORE: Engine sensor questions
Repair Topics /
Engine Sensors-1
/ Engine Sensors-2
Look up
your engine sensor question in our Car
Repair forum section.
Got Car Repair Questions?
We will answer it for FREE!
Related Subjects
GET ONLINE
CAR REPAIR MANUALS
Get instant access to your vehicles drive belt routing, wiring diagrams, trouble
code information, updates and factory bulletins.
| 
